The development of visual acuity is being studied in infants, by means of a behavioral technique, forced-choice preferential looking (FPL). The development of acuity is being followed longitudinally in individual infants, and additional infants are being studied cross-sectionally at the same ages used for testing the longitudinal sample. Preliminary age norms have been generated from this project. A quick, efficient version of the technique is also being developed for possible clinical screening of infant vision. Preliminary results suggest that the technique can discriminate infants who would be expected to have poor binocular visual acuity from infants who would be expected to have normal binocular visual acuity.